For the last two months, Beccy and Austin Craig haven’t spent any cash. Well, they’ve spent money, but all of their transactions are with the virtual currency called Bitcoin. Yes, that’s the same stuff that all the transactions on illegal drug website Silk Road were made in.

But apparently it can be used by a sweet couple from Utah too. They use it for all of their daily shopping, including gas and food, and now they’re taking it international: next week the couple is road tripping to New York City and from there they will fly to Stockholm. And it will all be done on Bitcoin, a decentralized, peer-to-peer digital currency.The Craigs are part of a documentary project, “Life on Bitcoin” and in Sweden they will visit a company that makes “Bitcoin mining machines,” basically computers that manage the Bitcoin, not mining actual coins.

But how exactly does one travel using a virtual currency? Carefully. While the Craigs have found a community in and around Provo that supports the use of Bitcoins and their “online wallet,” in order to survive in other places, they have to hope that they can find the same. If it’s late at night and you’re in the middle of nowhere on a highway, you can’t just go buy a few candy bars and chips at the local gas station.

The Craigs purchased their tickets to Sweden from a German travel agent that deals in Bitcoin. But beyond that, their travels are unplanned, besides hoping to tap into local Bitcoin user communities. Which raises the question: is it really possible to travel using only a virtual currency?

Since it’s virtual, Bitcoin coins don’t represent any actual currency, which means no need for thinking about exchange rates, but how do you buy metro tickets? What about if you have an accident and end up having to pay to see a doctor? What about going out for a local brew?

The Craigs will simply have to wait and see, but we can all hope that they pack some extra provisions with them before they leave.